In a standard pergola, the control box is typically placed in the side beams, with the power cord running through one of the back two posts (columns). However, in the wall-mounted configuration, there are no back posts/columns to route the cable through.
If the customer would like the power to run through the back in this case, they can install the cable as shown in the image to the right.
It’s important to remind them to ground their grounding wire to the wall or surface they are anchoring the pergola to, ensuring safety and proper installation.